A communication environment between devices will be briefly described hereinbelow. Machine-to-Machine (M2M) communication refers to communication between electronic devices in the literal sense of the word. In a broad sense, M2M communication means wired or wireless communication between electronic devices or communication between devices controlled by people. Recently, M2M communication generally refers to wireless communication between electronic devices, performed without intervening people. In the early 1990s when the concept of M2M communication was first introduced, M2M communication was recognized as the concept of a remote control, telematics, etc. and a derivative market was very limited. However, as M2M communication has rapidly been developed in the past few years, it has grown as a market receiving attention from the whole world. In particular, M2M communication has exerted an important influence on the field of fleet management in a Point Of Sale (POS) system and a security related application market, remote monitoring of machines or facilities, and smart meter for measuring an operating time of mechanical construction equipment and automatically measuring heat or the used amount of electricity. Future M2M communication will be used for various uses in association with existing mobile communication, wireless high-speed Internet, and low-output communication solution such as Wi-Fi and ZigBee and will be extended up to a Business-to-Consumer (B2C) without being confined to a Business-to-Business (B2B) market any longer.
In M2M communication, all machines equipped with a Subscriber Identity Module (SIM) card are able to transmit and receive data so that they can be remotely managed and controlled. For example, M2M communication technology can be used for numerous machines and equipment such as automobiles, trucks, trains, containers, vending machines, gas tanks, etc., and an application range thereof is very extensive.
Conventionally, it was general to individually manage mobile stations so that one-to-one communication was mainly performed between a base station and a mobile station. Assuming that numerous M2M devices communicate with the base station through one-to-one communication, network overload is expected due to signaling generated between each of the M2M devices and the base station. If M2M communication is rapidly spread and extensively used as described above, an overhead problem may occur due to communication between the M2M devices or between the M2M devices and the base station.
Further, since a human does not participate in operations of M2M devices in an M2M system, an abnormal power outage event may occur in M2M devices. Then the power outage event may also occur in most M2M devices at a location to which the corresponding M2M devices belong.
If a power outage event occurs, the M2M devices should report the power outage event to the base station. For example, M2M devices in an idle state will perform a ranging procedure in order to report the outage event and then collision may occur between the M2M devices. Moreover, the M2M devices in a normal state will perform a bandwidth request procedure to report the power outage event and then there is a high possibility of collision between the M2M devices.
If M2M devices collide with each other, a collision resolution procedure is performed to restore a collision state. Accordingly, upon occurrence of an abnormal power outage event, unnecessary power may be consumed in M2M devices and efficiency of system resources may be deteriorated.